化简sin40度(tan10度减根号3)跪求

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化简sin40度(tan10度减根号3)跪求化简sin40度(tan10度减根号3)跪求化简sin40度(tan10度减根号3)跪求sin40°(tan10°-√3)=sin40°(sin10°/co

化简sin40度(tan10度减根号3)跪求
化简sin40度(tan10度减根号3)跪求

化简sin40度(tan10度减根号3)跪求
sin40°(tan10°-√3)
=sin40°(sin10°/cos10°-√3)
=sin40°(sin10°-√3cos10°)/cos10°
=2sin40°[sin10°cos60°-cos10°sin60°]/cos10°
=2sin40*sin(-50°)/cos10°
=-2sin40°cos40°/cos10°
=-sin80°/cos10°
=-1


sin40°(tan10°-√3)
=sin40°*2*(1/2*sin10°-√3/2*cos10°)/cos30°
=2sin40°(cos60°sin10°-sin60°cos10°)/cos10°
=2sin40°[sin10°cos60°-cos10°sin60°]/cos10°
=2sin40*sin(-50°)/cos10°
=-2sin40*sin50°/cos10°
=-2sin40°cos40°/cos10°
=-sin80°/cos10°
=-cos10°/cos10°
=-1

我认为以下俩回答都是正确的!!!